Passively Mode-Locked Tm:YAG Ceramic Laser Based on Graphene

There is a growing interest in developing ultrafast laser sources around 2-μm wavelength range. Here, we experimentally demonstrate a diode-pumped passively mode-locked Tm:YAG ceramic laser using graphene as a mode locker. By transferring graphene synthesized by chemical vapor deposition onto Au-coated mirror as saturable absorber, continuous wave mode locking is successfully obtained in the Tm:YAG ceramic laser. The generated mode-locked pulses in 2-μm spectral region have a pulse width as short as 2.8 ps, with a maximum average output power of 158 mW and repetition rate of 98.7 MHz. The mode-locked mid-infrared pulses are very stable having a multitude of potential applications such as ultrafast molecule spectroscopy, mid-IR nonlinear frequency conversion, etc.